Logic tells me if there were Curses against and protective spells for defeating Tomb Robbery by the 6th Dynasty (probably earlier) then there HAD to be Tomb Robbers.
Why would they have Laws against, Curses to punish for, and Blessings to protect against, something that hadn't happened yet?
No, my personal belief is the mortar and paint in the very first tomb was still curing when the first tomb robbers were scheming out how to get at the goodies.
I agree with BA "Pistol" Hokum that the vast majority of society may have reacted with horror at the act, but it only takes a handful who wish the proceeds to, well, proceed.
And if the Tomb of the Unknown Soldier had a solid gold full size rifle with 2 carat diamonds on his uniform, SOMEONE would be risking breaking in even if the rest of us would geld him for trying.
Jammer
